Description from Flora of China
Herbs erect or sprawling, 30-80 cm tall, glabrous or sparsely pubescent with simple and glandular hairs. Stolons bearing underground tubers; tubers white, red, or purplish, globose, oblate, or elliptic, 3-10 cm in diam., fleshy. Leaves interruptedly odd-pinnate, with 6-8 pairs of leaflets and smaller, unequal interstitial leaflets; petiole 2.5-5 cm; leaflet blade ovate or oblong, mostly sparingly pilose. Inflorescences appearing terminal, leaf opposed, or axillary, many-flowered, sparingly branched panicles. Pedicel articulate near middle, 1-2 cm. Calyx sparsely pubescent; lobes lanceolate. Corolla white, pink, or blue-purple, sometimes all on 1 plant, rotate, 2.5-3 cm in diam.; lobes deltate, ca. 5 mm. Filaments ca. 1 mm; anthers 5-6 mm. Ovary glabrous. Style ca. 8 mm. Berry green or yellowish green, often striped, globose, smooth, ca. 1.5 cm in diam. Fl. and fr. summer and autumn.
Widely cultivated throughout China, also in other temperate regions of the world [Native to South America]